The present invention relates to an air bag having a closable vent. The present invention is applicable to all known types of air bags including: driver, passenger, curtain and seat-mounted side impact air bags and systems therefore.
Reference is briefly made to FIGS. 1 and 2, which show a conventional passenger-side air bag system 20. System 20 includes air bag 22 and an inflator 24. The air bag is configured to have an inlet 26 to receive inflation gas from inflator 24. The air bag is also configured to have one or more inflatable chambers 28. Inflator 24 is secured to a vehicle component such as a structural support member below the instrument panel. If air bag 24 is a driver side air bag, a curtain air bag, knee bag or a seat-mounted air bag, then the structural element is the steering wheel, roof rail, instrument panel support or seat.
FIGS. 1 and 2 further show the construction of a conventional passenger side air bag 22. Often air bags such as 22 utilize identical side panels 40 and 42 sewn to an elongated main panel 44. The above-mentioned inlet 26 is formed at the common region of each of the above panels 40, 42 and 44. Often, driver, passenger or other types of air bags include vents or exit ports such as 46 in each of the side panels 40 and 42. These vents 46 can be configured as openings in a panel or as high permeability areas in the panel. Typical of air bag construction is that each of the panels 40, 42 and 44 is made of woven nylon or polyester. These panels may be coated or uncoated and, as known in the art, the permeability of uncoated panels can be controlled utilizing various weaving techniques.
The purpose of a vent is to provide a path such that inflation gas can exit the air bag. It has been found desirable to keep the vent open while the fully inflated shape of the air bag has not been achieved and to close the vent when the air bag is fully inflated. In certain situations, the occupant to be protected is not sitting properly in his or her seat; generally, the occupant is said to be sitting in an “out-of-position” (OOP) position or orientation. One such out-of-position orientation is with the occupant bent forwardly toward the location of the non-inflated air bag. In this situation, the occupant's body will impact the inflating air bag prior to the air bag becoming fully inflated. It has been shown desirable to slow the inflation of the air bag, in the condition recited above, by permitting the vents to stay open, allowing inflation gas to leave the air bag, which among other things lessens the impact velocity of the bag with the occupant.
It is an object of the present invention to provide an air bag having a vent closure mechanism that closes associated air bag vents as the air bag becomes fully inflated.
Accordingly the invention comprises: a safety system comprising an air bag configured to have at least one inflatable volume or chamber, an inlet through which inflation gas enters the inflatable volume, the air bag including at least one exit port or vent which, when in an open state, permits inflation gas to exit the volume or chamber, the exit port or vent located in a selected region of the air bag, a vent closure mechanism secured to the air bag and movable to close the exit port or vent by tension created in a tether, which is part of the vent closure mechanism; as the air bag inflates, the tether has one end operatively secured to the air bag, a second end operatively secured to the vent closure mechanism, the tether including a medial portion slidably guided across a portion of the air bag.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.